The overall objective of this renewal grant is the continued development, evaluation and utilization of pulsed Doppler ultrasound. The ultimate intention of the investigators is to use the pulsed Doppler system to obtain meaningful physiological and pharmacological data from human patients with naturally occurring cardiovascular diseases and from animal models developed to test new and promising cardioactive drugs. Progress to date, supported by the current pulsed Doppler grant (HL-15706), has indicated the feasibility of using pulsed Doppler ultrasound to 1) Measure coronary artery flow velocity at the time of diagnostic coronary arteriography. 2) Obtain noninvasive cross-sectional images of superficial vessels and 3) record blood flow simultaneously from several vascular beds in conscious, unrestrained laboratory animals. During the period of this proposed renewal grant, engineering developments and evaluation will continue in all of these areas. In addition, complex physiologic and pharmacologic studies are planned using pulsed Doppler ultrasound systems in both the human cardiac catheterization laboratory and the animal research laboratory. Finally, collaborations will continue to be established with other investigators who are interested in corporating our pulsed Doppler techniques into their research projects. These collaborations hopefully will increase the growth of the pulsed Doppler field.